Breeding method of female pig for propagation and feed for female pig for propagation

ABSTRACT

Disclosed are a breeding method of a female pig for propagation characterized by feeding at least one lipid selected from a fatty acid having 12 to 24 carbon atoms which has a melting point falling in a range of −60 to 40° C. and an iodine value falling in a range of 30 to 470 and which has 2 to 6 double bonds in a molecule, a triglyceride containing the above fatty acid and a metal salt of the above fatty acid, and a feed for a female pig for propagation containing the above lipid in a proportion of 0.5 to 10 % by weight in terms of the fatty acid described above.  
     According to the breeding method of a female pig for propagation of the present invention, breeding results can be elevated by further increasing a litter size, allowing the number of delactation to grow large, shortening the days of returning estrus and increasing an annual average delivery frequency.

TECHNICAL FIELD

[0001] The present invention relates to a breeding method of a femalepig for propagation and a feed for a female pig for propagation. Morespecifically, the present invention relates to a breeding method of afemale pig for propagation for elevating a propagation result of a pigby further increasing a litter size, elevating the number ofdelactation, shortening the days of returning estrtus and allowing anannual average delivery frequency to grow, and a feed for a female pigfor propagation which is suitably used in this breeding method.

BACKGROUND ART

[0002] So-called lipids such as triglycerides and fatty acids areexcellent particularly as an energy source among three essentialnutrients and have so far widely been used for a feed for livestock(refer to, for example, ┌Animal Dietetics┘ H. Morimoto, Yokendo, 1987).Among them, triglyceride is not isolated in the form of triglyceride andfed in almost all cases in the form of a material itself containing alot of triglycerides such as soybean, rapeseed, corn, cotton seed andrice bran or cakes containing triglycerides obtained after pressing oilsfrom the above materials (┌Japan Standard Feed Component Table┘ editedby an executive office of Fisheries Technology Conference in Ministry ofAgriculture and Fisheries, Japan Livestock Industry Association, 1995).In recent years, fatty acids obtained by hydrolyzing this triglyceride,particularly hardened fatty acids such as beef tallow and palm oil tendto be used in many cases because of easiness in handling.

[0003] These triglycerides and fatty acids have been used blending withgeneral mixed feeds for the purpose of efficiently supplying energy andhave not been used for the purpose of improving a breeding efficiencypaying attentions to a physiological activity of a specific fatty acid.With respect to this point, only evaluation of fat and oil raw materialsand fats and oils as energy sources such as a digestible nutrient totalamount and metabolizable energy is described in the Japan Standard FeedComponent Table described above which is a leading standard book oflivestock nutrient in our country.

[0004] On the other hand, fatty acid calcium salt which is one of lipidsis a relatively new material which came to be first used as a feed in1980s. This fatty acid calcium salt is widely used as a high energy feedfor livestock such as high yielding dairy cows and others, particularlyfor supplying energy in a hot weather (refer to, for example,┌Utilization Data of Fat and Oil to Cow Feed┘ The National Federation ofDairy Cooperative Associations, 1988). Further, known as other uses area method in which this fatty acid calcium salt is used for supplyingenergy which is liable to be short when feeding mainly grass for agrowth in rumen in breeding beef cattles, whereby a healthy growth inrumen and a good grown body are obtained (┌Beef Cattle Journal, Februaryissue, March issue, July issue, August issue and September issue┘ T.Terada, 1997), a method in which calcium salt of fatty acid contained infish oil is fed to cattles and pigs to introduce eicosapentaenoic acidand docosahexaenoic acid into meats (Japanese Patent ApplicationLaid-Open No. 289734/1996), a method in which calcium salt of fatty acidcontained in linseed oil is fed to milking cows to introduce α-linolenicacid into milk ( ┌Nicchiku Report┘ vol. 66, No. 10, p. 889 to 897, S.Ishida et al., 1995) and a method in which calcium salt of fatty acidcontained in linseed oil is fed to egg breed chickens to introduceα-linolenic acid into eggs (Japanese Patent Application Laid-Open No.315350/1994).

[0005] As described above, all of a triglyceride, a fatty acid and fattyacid calcium salt have so far widely been used as a raw material for afeed, and they have been used in almost all cases for the purpose of (1)growing a body and improving production of milk by efficiently supplyingenergy or (2) introducing some kinds of fatty acids into livestocks suchas beef, milk, pork, chickens and eggs.

[0006] In recent years, attentions are paid to a physiological activityof unsaturated fatty acids such as linoleic acid, linolenic acid,eicosapentaenoic acid and docosahexaenoic acid as new uses of theselipids, and it is tried to make use of them for breeding of cattles (┌Clinical Veterinary┘ vol. 14, No. 7, p. 33 to 39, M. Nishikai, 1996;Feetstuffs, Staples, C. R. et al., Jan. 12, 1998). Further, it isreported that these unsaturated fatty acids reduce a death rate offertilized ovums, which results in elevating a fecundation rate ofcattles (Thatcher, W. W. et al., J. Anim. Sci., 72 (Suppl. 3), p. 16 to30, 1994).

[0007] As described above, researches regarding a relationship of abreeding result with triglycerides, fatty acids and derivatives thereofand applications thereof in breeding cattles have come to be carriedout, but it is the existing situation that a relationship thereof withtriglyceride, fatty acids and derivatives thereof in breeding pigs havenot yet been researched. That is, as far as breeding of pigs isconcerned, it has so far actively been tried to elevate an abilityintrinsic to pigs by breeding based on a thremmatological method, and alitter size per head of a mother pig has come to reach, for example, 12head/parturition on an average. However, it has not yet been tried toelevate a breeding result thereof from the viewpoints of nutrients suchas feed components and physiologically active substances contained infeeds.

DISCLOSURE OF THE INVENTION

[0008] In light of the circumstances described above, an object of thepresent invention is to provide a breeding method of a female pig forpropagation for elevating a breeding result of pigs by (1) increasing alitter size, (2) elevating the number of delactation, (3) shortening thedays of returning estrus and (4) increasing an annual average deliveryfrequency. A second object thereof is to provide a feed for a female pigfor propagation which is suitably used in this breeding method.

[0009] Thus, intensive researches repeated by the present inventors inorder to achieve the objects described above have resulted in findingthat the first object can be achieved by feeding a female pig forpropagation with a lipid comprising a fatty acid having a prescribedcarbon number in which a melting point and an iodine value each fall ina specific range and which has plural double bonds in a molecule andtriglyceride and a metal salt thereof and that the second object can beachieved by a feed containing the lipid described above in a specificproportion. The present invention has completed based on such knowledge.

[0010] That is, the first object of the present invention can beachieved by a breeding method of a female pig for propagationcharacterized by feeding a feed comprising at least one lipid selectedfrom a fatty acid having 12 to 24 carbon atoms which has a melting pointfalling in a range of −60 to 40° C. and an iodine value falling in arange of 30 to 470 and which has 2 to 6 double bonds in a molecule, atriglyceride containing the above fatty acid and a metal salt of theabove fatty acid, particularly a feed containing a lipid comprising ametal salt of the above fatty acid and, if necessary, a triglyceridecontaining the above fatty acid.

[0011] Further, the second object thereof can be achieved by a feed fora female pig for propagation characterized by comprising at least onelipid selected from a fatty acid having 12 to 24 carbon atoms which hasa melting point falling in a range of −60 to 40° C. and an iodine valuefalling in a range of 30 to 470 and which has 2 to 6 double bonds in amolecule, a triglyceride containing the above fatty acid and a metalsalt of the above fatty acid in a proportion of 0.5 to 10% by weight interms of the fatty acid described above.

BEST EMBODIMENT FOR CARRYING OUT THE INVENTION

[0012] In the breeding method of a female pig for propagation of thepresent invention (hereinafter referred to merely as ┌the breedingmethod of the present invention┘ ), fed with a female pig forpropagation is at least one lipid selected from an unsaturated fattyacid, a triglyceride containing the above fatty acid and a metal salt ofthe above fatty acid.

[0013] Used as the unsaturated fatty acid described above is a fattyacid having 12 to 24 carbon atoms which has a melting point falling in arange of −60 to 40° C., preferably −50 to 0° C. and an iodine valuefalling in a range of 30 to 470, preferably 150 to 470 and which has 2to 6 double bonds in a molecule. Capable of being preferably given assuch fatty acid is at least one selected from linoleic acid, linolenicacid, bishomo-γ-linolenic acid, arachidonic acid and eicosapentaenoicacid.

[0014] Shown in Table 1 are the carbon numbers, the double bond numbers,the melting points and the iodine values of the respective fatty acids.TABLE 1 Kind of fatty Carbon Number of Melting Iodine Acid number doublebond point (° C.) value Myristic acid C₁₄ 0 54.4 0 Palmitic acid C₁₆ 062.9 0 Palmitoleic C₁₆ 1 0.5 99.8 Acid Stearic acid C₁₈ 0 69.6 0 Oleicacid C₁₈ 1 13.4 89.9 Linoleic acid C₁₈ 2 −5.1 181.0 Linolenic acid C₁₈ 3−11.2 273.5 Bishomo-γ- C₂₀ 3 About −10 248.5 linolenic acid ArachidonicC₂₀ 4 −49.5 333.4 Acid Eicosa-pentaenoic C₂₀ 5 −54.0 419.5 acidDocosahexaenoic C₂₂ 6 −44.5 463.6 Acid

[0015] The preceding respective fatty acids given as examples can beobtained by hydrotically treating plant oils such as, for example,soybean oil, rapeseed oil, corn oil, safflower oil, sunflower oil, riceoil, beefsteak plant oil, evening primrose oil, borage oil and linseedoil, fish oils obtained from oceanic bonito, mackerel, sardine and tunaand fats and oils such as triglycerides originating in variousmicroorganisms such as Conidiobolus genus of Entomophthorales. sp.,Entomophthora genus, Mucor. sp. and Mortierella genus.

[0016] The fats and oils described above can be given as triglyceridescontaining the above fatty acids. Among these fats and oils, preferablyused in the present invention are those having high contents of linoleicacid, linolenic acid, bishomo-γ-linolenic acid, arachidonic acid andeicosapentaenoic acid.

[0017] On the other hand, the metal salts of the above fatty acids aresuitably calcium salts and magnesium salts of the various fatty acidsdescribed above, and they may be used alone or in combination of two ormore kinds thereof. A production process of the metal salts of thesefatty acids shall be explained later in details.

[0018] The breeding method of the present invention is preferablyapplied to female pigs bleeded by artificial insemination, and a feedingamount per day of at least one fatty acid selected from linoleic acid,linolenic acid, bishomo-γ-linolenic acid, arachidonic acid andeicosapentaenoic acid falls usually in a range of 20 to 200 g,preferably 30 to 180 g. The preceding feeding amount of less than 20 gdoes not allow the effects of these fatty acids to be sufficientlyexhibited. On the other hand, the amount fed in excess of 200 g does notprovide more effects and allows an adverse effect exerted by excessenergy to grow large.

[0019] In the present invention, preferably used as the lipid describedabove are those containing at least one fatty acid selected fromlinoleic acid, linolenic acid, bishomo-γ-linolenic acid, arachidonicacid and eicosapentaenoic acid in a proportion of 20 to 99% by weight.If this content is less than 20% by weight, a large amount of the lipidhas to be fed in order to feed at least one fatty acid selected fromlinoleic acid, linolenic acid, bishomo-γ-linolenic acid, arachidonicacid and eicosapentaenoic acid in an amount of 20 g or more per day. Asa result thereof, the breeding efficiency is likely to be reducedbecause of a problem of excess growth brought about by excess energy,and a content of the other nutrients (carbohydrates, proteins and thelike) is likely to be relatively reduced.

[0020] The triglycerides and fatty acids described above are liquid at aroom temperature if linoleic acid, linolenic acid, bishomo-γ-linolenicacid, arachidonic acid or eicosapentaenoic acid is contained in aproportion of 20% by weight or more, but fatty acid calcium salts andfatty acid magnesium salts are solid. In terms of easiness in handlingand easiness in admixing with a feed, these fatty acid metal salts arepreferred among the lipids. In particular, solid powdery or granularfatty acid calcium salts and fatty acid magnesium salts are preferablyused.

[0021] In the present invention, the triglycerides, fatty acids or fattyacid metal salts described above can be used in a mixture withconventional base feeds. Feeds which are usually available in the marketfor female pigs for propagation or fatting, for example, a feed havingthe following blending composition can be used as the base feed: % byweight Bran 50.0 Milo 21.2 Soybean cake 20.0 Fish meal 3.0 Molasses 4.0Minerals 1.53 Vitamines 0.27

[0022] A blending proportion of the base feed to at least one lipidselected from the fatty acids described above, the triglycerides thereofand the metal salts of the above fatty acids is preferably decided sothat at least one selected from linoleic acid, linolenic acid,bishomo-γ-linolenic acid, arachidonic acid and eicosapentaenoic acid iscontained in a feed taken by a head per day in an amount of 20 to 200 gin terms of the fatty acid described above. In this case, the contentsof linoleic acid, linolenic acid, bishomo-γ-linolenic acid, arachidonicacid or eicosapentaenoic acid contained in both of the base feed and theabove lipid have to be considered, and they are controlled by thefollowing method.

[0023] First of all, when the base feed is compounded with soybean,soybean cake, powdered blood and fish meal, there is a possibility thatlinoleic acid, linolenic acid, bishomo-γ-linolenic acid, arachidonicacid and eicosapentaenoic acid are contained as well in them, so thatthese base feeds are treated in advance with a solvent ofchloroform/methanol=2/1to extract a lipid fraction, and this fractionhas to be analyzed by a gas chromatography to determine a content of atleast one selected from linoleic acid, linolenic acid,bishomo-γ-linolenic acid, arachidonic acid and eicosapentaenoic acid.Secondly, linoleic acid, linolenic acid, bishomo-γ-linolenic acid,arachidonic acid and eicosapentaenoic acid which are contained in thelipid described above are added to linoleic acid, linolenic acid,bishomo-γ-linolenic acid, arachidonic acid and eicosapentaenoic acidwhich are contained in this base feed to control the feeding amount sothat the feeding amount comes to 20 to 200 g per day in terms of thefatty acid described above.

[0024] The feed intake amount per day is different depending on thebreed of a pig used and falls in a range of about 2 to 4 kg per head.Considering, for example, a case where the feed intake amount is set atabout 3.5 kg/day/head, it is assumed that analysis of the base feeddescribed above shows a linoleic acid content of 10 g in 3.5 kg of thebase feed. Accordingly, in this case, the lipid corresponding to 10 to190 g of linoleic acid, linolenic acid, bishomo-γ-linolenic acid,arachidonic acid or eicosapentaenoic acid has to be added. Thus,blending 20 to 380 g of soybean oil having a linoleic acid content of50% by weight with this base feed results in providing a feed having theintended composition. This feed may be used in the form of powderobtained merely by blending, a so-called mash type or may be used in apelletized form obtained by means of a suitable extrusion-moldingmachine.

[0025] In the breeding method of the present invention, a duration offeeding female pigs. with the feed described above extends from 30 daysbefore artificial insemination up to 3 weeks after the artificialinsemination. That is, the feed comprising the lipid containing at leastone fatty acid selected from linoleic acid, linolenic acid,bishomo-γ-linolenic acid, arachidonic acid and eicosapentaenoic acid isfed in a duration extending from 30 days before artificial inseminationup to 3 weeks after the artificial insemination. In this case, the feedis preferably fed in a proportion of 2 to 4 kg per head a day and 20 to200 g per head a day in terms of the fatty acids described above. In thepresent invention, an amount corresponding to the amount achieved byfeeding the feeding amount described above every day in the durationdescribed above may be fed in any period in the duration describedabove, but taking the effects of the present invention intoconsideration, the amount described above is preferably fed every day inthe duration described above. When the desired feeding amount is notachieved in the duration described above, the breeding result-improvingeffect becomes unsatisfactory, and therefore it is not preferred. In thepresent invention, the feed is preferably fed so that the total amountof the above fatty acid reaches 1500 to 9000 g per head.

[0026] The present invention provides a feed for a female pig forpropagation (hereinafter referred to merely as ┌the feed of the presentinvention┘ ).

[0027] The feed of the present invention comprises at least one lipidselected from a fatty acid having 12 to 24 carbon atoms which has amelting point falling in a range of −60 to 40° C., preferably −50 to 0°C. and an iodine value falling in a range of 30 to 470, preferably 150to 470 and which has 2 to 6 double bonds in a molecule, a triglyceridecontaining the above fatty acid and a metal salt of the above fatty acidin a proportion of 0.5 to 10% by weight in terms of the fatty aciddescribed above.

[0028] In the feed of the present invention, the fatty acid describedabove and the like have a content falling preferably in a range of 1 to8% by weight, particularly suitably 1.1 to 6% by weight in terms of thefatty acid from the viewpoint of effectively feeding the feed.Preferably used as this fatty acid is at least one selected fromlinoleic acid, linolenic acid, bishomo-γ-linolenic acid, arachidonicacid and eicosapentaenoic acid.

[0029] Calcium salts and magnesium salts of the above fatty acids arepreferred as the fatty acid metal salt. In particular, suited are fattyacid calcium salt and fatty acid magnesium salt containing at least oneselected from linoleic acid, linolenic acid, bishomo-γ-linolenic acid,arachidonic acid and eicosapentaenoic acid in a proportion of 20 to 99%by weight. They may be used alone or in combination of two or more kindsthereof.

[0030] Among the lipids described above, these fatty acid metal saltsare suited in terms of easiness in handling and easiness in admixingwith the feed.

[0031] In the feeds of the present invention, particularly suited is thefeed produced by blending the base feed with a metal salt of at leastone fatty acid obtained by decomposing or refining soybean oil, cornoil, rapeseed oil, sunflower oil, safflower oil, sesame oil, rice oil,beefsteak plant oil, evening primrose oil, borage oil, linseed oil, palmoil or fish oil. Especially, preferred is the feed produced by blendinga combination of the above metal salt with a triglyceride containing thefatty acid described above.

[0032] The metal salts of the fatty acids described above are producedby reacting the fatty acids with metal oxides or metal hydroxides, andpreferred are those produced by means of an extruder having at least araw material-feeding zone, a kneading and reacting zone and a coolingzone. Further, suited are those produced by controlling a temperature ofthe raw material-feeding zone in the extruder to 20 to 80° C., atemperature of the kneading and reacting zone to 80 to 200° C. and atemperature of the cooling zone to −20 to 5° C.

[0033] The extruder described above is a pressure extruder having a rawmaterial-feeding zone, a reacting zone and a cooling zone, and capableof being used are those of a single shaft type in which one rotatingscrew is inserted into a cylinder and a two shaft type in which twoscrews rotating in the same direction or different directions areinserted into a cylinder, and having a cross section of an 8 charactertype. In particular, the extruder of a two shaft type is preferably usedin the present invention in terms of a kneading capacity. The screw inthis extruder of a two shaft type is used by suitably combining pluralparts which can usually carry out operations such as delivering,reversing and kneading.

[0034] The cylinder part of this extruder is divided into plural barrelscorresponding to a raw material-feeding zone, a kneading and reactingzone and a cooling zone, and external jackets are installed in thecircumferences of the respective barrels, wherein a specification whichcan meet both heating and cooling can be employed so that the jacketscan be applied to any of the zones described above by each barrel.

[0035] In the present invention, a temperature of a raw material-feedingsite in the raw material-feeding zone is maintained at 20 to 80° C.,preferably 30 to 70° C., and fatty acid, metal oxide or metal hydroxideand water are introduced to control a temperature of a kneading andreacting site in the kneading and reacting zone is maintained at 80 to200° C., preferably 100 to 190° C. to react them to form a fatty acidmetal salt. Further, a cooling site in the cooling zone is maintained ina range of −20 to 5° C., preferably −15 to 0° C. for cooling, wherebythe desired fatty acid metal salt is advantageously produced.

[0036] Next, the present invention shall more specifically be explainedwith reference to examples, but the present invention shall by no meansbe restricted by these examples.

PREPARATION EXAMPLE 1

[0037] The composition of a mixed feed used as a base feed is shown inTable 2. TABLE 2 Components % by weight Bran 50.00 Milo 21.20 Soybeancake 20.00 Fish meal 3.00 Molasses 4.00 Minerals 1.53 Vitamines 0.27

[0038] Crude fat contained in this base feed was extracted and analyzedby a gas chromatography to find that contained in 1 kg were 2 g oflinoleic acid, 1 g of linolenic acid and 1 g of eicosapentaenoic acid.Bishomo-γ-linolenic acid and arachidonic acid were not containedtherein.

[0039] Triglycerides having a fatty acid composition shown in Table 3were used to prepare mixed feeds in a composition shown in Table 4. Thecontents of linoleic acid, linolenic acid and eicosapentaenoic acid(hereinafter abbreviated as EPA) contained in the finished mixed feedswere shown as well in Table 4. The feeds thus obtained were designatedas Samples 1 to 18. TABLE 3 Fatty acid composition (% by weight) Beeftallow Sunflower Safflower Kind of fatty acid hardened oil Soybean oiloil oil Linseed oil Borage oil Myristic acid 4.0 — — — — 0.1 Palmiticacid 31.1 10.4 6.7 6.8 6.6 10.6 Palmitoleic acid 0.9 — — — — 0.5 Stearicacid 60.0 4.0 4.0 2.5 2.9 4.0 Oleic acid 4.0 23.5 17.9 12.6 19.5 17.3Linoleic acid 53.5 69.8 77.4 23.4 37.1 Linolenic acid 8.3 0.9 0.1 46.623.2 Others 0.3 0.7 0.6 1.0 7.3

[0040] TABLE 4 Sample Base Linoleic Linolenic EPA No. Triglyceride (g)feed (kg) acid (g) acid (g) (g) Sample 1 Beef tallow 3.45 6.90 3.45 3.45hardened oil (50) Sample 2 Soybean oil (50) 3.45 30.98 7.19 3.45 Sample3 Sunflower oil (50) 3.45 38.31 3.86 3.45 Sample 4 Safflower oil (50)3.45 41.73 3.50 3.45 Sample 5 Linseed oil (50) 3.45 18.33 24.42 3.45Sample 6 Borage oil (50) 3.45 23.60 13.89 3.45 Sample 7 Beef tallow 3.356.70 3.35 3.35 hardened oil (150) Sample 8 Soybean oil (150) 3.35 78.9314.56 3.35 Sample 9 Sunflower oil (150) 3.35 103.60 4.57 3.35 Sample 10Safflower oil (150) 3.35 111.20 3.49 3.35 Sample 11 Linseed oil (150)3.35 37.39 66.26 3.35 Sample 12 Borage oil (150) 3.35 56.79 34.67 3.35Sample 13 Beef tallow 3.25 6.50 3.25 3.25 hardened oil (250) Sample 14Soybean oil (250) 3.25 126.90 21.93 3.25 Sample 15 Sunflower oil (250)3.25 163.60 5.28 3.25 Sample 16 Safflower oil (250) 3.25 180.70 3.483.25 Sample 17 Linseed oil (250) 3.25 59.15 108.10 3.25 Sample 18 Borageoil (250) 3.25 90.00 55.45 3.25

PREPARATION EXAMPLE 2

[0041] Fatty acids having compositions shown in Table 5 were used toprepare mixed feeds having compositions shown in Table 6. The feed shownin Table 2 in Preparation Example 1 was used for the base feed. Thefeeds thus obtained were designated as Samples 19 to 39. TABLE 5 Fattyacid composition (% by weight) Beef tallow Sunflower Safflower Extra α-Linseed Borage Kind of fatty hardened oil Soybean oil oil fatty oilfatty Linolenic oil fatty oil fatty acid fatty acid fatty acid acid acid70 acid acid Myristic acid 4.0 — — — — — 0.1 Palmitic acid 31.1 10.4 6.76.8 — 6.6 10.6 Palmitoleic 0.9 — — — — — 0.5 acid Stearic acid 60.0 4.04.0 2.5 — 2.9 4.0 Oleic acid 4.0 23.5 17.9 12.6 4.0 19.5 17.3 Linoleicacid 53.5 69.8 77.4 22.5 23.4 37.1 Linolenic 8.3 0.9 0.1 73.5 46.6 23.2acid Others 0.3 0.7 0.6 — 1.0 7.3

[0042] TABLE 6 Sample Base Linoleic Linolenic EPA No. Fatty acid (g)feed (kg) acid (g) Acid (g) (g) Sample 19 Beef tallow 3.45 6.90 3.453.45 hardened oil (50) Sample 20 Soybean oil (50) 3.45 33.65 7.60 3.45Sample 21 Sunflower oil (50) 3.45 41.80 3.90 3.45 Sample 22 Saffloweroil (50) 3.45 45.60 3.50 3.45 Sample 23 Extra α-Linolenic 3.45 18.1540.20 3.45 70 (50) Sample 24 Linseed oil (50) 3.45 19.60 26.75 3.45Sample 25 Borage oil (50) 3.45 25.45 15.05 3.45 Sample 26 Beef tallow3.35 6.70 3.35 3.35 hardened oil (150) Sample 27 Soybean oil (150) 3.3586.95 15.80 3.35 Sample 28 Sunflower oil (150) 3.35 114.40 4.70 3.35Sample 29 Safflower oil (150) 3.35 122.80 3.50 3.35 Sample 30 Extraα-Linolenic 3.35 40.45 113.60 3.35 70 (150) Sample 31 Linseed oil (150)3.35 41.80 73.25 3.35 Sample 32 Borage oil (150) 3.35 62.35 38.15 3.35Sample 33 Beef tallow 3.25 6.50 3.25 3.25 hardened oil (250) Sample 34Soybean oil (250) 3.25 140.30 24.00 3.25 Sample 35 Sunflower oil (250)3.25 181.00 5.50 3.25 Sample 36 Safflower oil (250) 3.25 200.00 3.503.25 Sample 37 Extra α-Linolenic 3.25 62.75 187.00 3.25 70 (250) Sample38 Linseed oil (250) 3.25 65.00 119.75 3.25 Sample 39 Borage oil (250)3.25 99.25 61.25 3.25

PREPARATION EXAMPLE 3

[0043] Used were seven kinds of beef tallow hardened oil fatty acid,sunflower oil fatty acid, soybean oil fatty acid, safflower oil fattyacid, linseed oil fatty acid, Extra α-Linolenic 70 and borage oil fattyacid in a composition shown in Table 5 (all manufactured by NOFCorporation) to prepare fatty acid calcium salts by the followingmethod.

[0044] Added to a reactor charged with 400 kg of water was 20 kg of finepowder-like calcium hydroxide (a product of Inoue Lime Co., Ltd.), andit was well stirred and dispersed. Dropwise added to the reactor in 30minutes while stirring was 100 kg of fatty acid which was heated inadvance to 60° C. to carry out neutralization. After finishing dropwiseadding, the solution was stirred and ripened for one hour and thenfiltered to collect fatty acid calcium salt. This filtered matter wasdried by hot air at 80° C. for 3 hours to obtain each 120 kg of therespective fatty acid calcium salts. Seven kinds of the fatty acidcalcium salts thus obtained were used to obtain samples in compositionsshown in Table 7, and they were designated as Samples 40 to 60. The feedshown in Table 2 in Preparation Example 1 was used for the base feed.TABLE 7 Sample Fatty acid calcium Base Linoleic Linolenic EPA No. salt(g) feed (kg) acid (g) Acid (g) (g) Sample 40 Beef tallow 3.45 6.90 3.453.45 hardened oil (50) Sample 41 Soybean oil (50) 3.45 30.98 7.19 3.45Sample 42 Sunflower oil (50) 3.45 38.31 3.86 3.45 Sample 43 Saffloweroil (50) 3.45 41.73 3.50 3.45 Sample 44 Extra α-Linolenic 3.45 17.0336.53 3.45 70 (50) Sample 45 Linseed oil (50) 3.45 18.33 24.42 3.45Sample 46 Borage oil (50) 3.45 23.60 13.89 3.45 Sample 47 Beef tallow3.35 6.70 3.35 3.35 hardened oil (150) Sample 48 Soybean oil (150) 3.3578.93 14.56 3.35 Sample 49 Sunflower oil (150) 3.35 103.60 4.57 3.35Sample 50 Safflower oil (150) 3.35 111.20 3.49 3.35 Sample 51 Extraα-Linolenic 3.35 37.08 102.6 3.35 70 (150) Sample 52 Linseed oil (150)3.35 37.39 66.26 3.35 Sample 53 Borage oil (150) 3.35 56.79 34.67 3.35Sample 54 Beef tallow 3.25 6.50 3.25 3.25 hardened oil (250) Sample 55Soybean oil (250) 3.25 126.90 21.93 3.25 Sample 56 Sunflower oil (250)3.25 163.60 5.28 3.25 Sample 57 Safflower oil (250) 3.25 180.70 3.483.25 Sample 58 Extra α-Linolenic 3.25 57.13 168.60 3.25 70 (250) Sample59 Linseed oil (250) 3.25 59.15 108.10 3.25 Sample 60 Borage oil (250)3.25 90.00 55.45 3.25

PREPARATION EXAMPLE 4

[0045] Fatty acids having fatty acid compositions shown in Table 8 wereused to prepare mixed feeds in compositions shown in Table 9. The feedshown in Table 2 in Preparation Example 1 was used for the base feed.Shown in Table 9 were the contents of linoleic acid, linolenic acid,bishomo-γ-linolenic acid, arachidonic acid and eicosapentaenoic acid(EPA) contained in the finished mixed feeds. The feeds thus obtainedwere designated as Samples 61 to 72. Extra Bishomo-γ-Linolenic 90, ExtraArachidonic 90 and Extra EPA 90 each shown in Table 8 are products ofNOF Corporation. TABLE 8 Fatty acid composition (% by weight) Beeftallow Extra Bishomo-γ- Extra Kind of fatty acid hardened oil Linolenic90 Arachidonic 90 Extra EPA 90 Myristic acid 4.0 — — — Palmitic acid31.1 — — — Palmitoleic acid 0.9 — — — Stearic acid 60.0 — — — Oleic acid4.0 — — — Linoleic acid — — — — Linolenic acid — 5.1 — —Bishomo-γ-linolenic acid — 93.5 5.5 — Arachidonic acid — 1.4 93.3 —Eicosapentaenoic acid — — — 92.9 Docosahexaenoic acid — — — 5.9 Others —— 1.2 1.2

[0046] TABLE 9 Sample Base Linoleic Linolenic BHGLN^(*1) Arachidonic EPANo. Fatty acid (g) feed (kg) acid (g) acid (g) (g) acid (g) (g) Sample61 Beef tallow 3.45 6.9 3.45 0 0 3.45 hardened oil (50) Sample 62EBLN-90^(*2) (50) 3.45 6.9 6.0 46.75 0.7 3.45 Sample 63 EAA-90^(*3) (50)3.45 6.9 3.45 2.75 46.55 3.45 Sample 64 EEPA-90^(*4) (50) 3.45 6.9 3.450 0 49.9 Sample 65 Beef tallow 3.35 6.7 3.35 0 0 3.35 hardened oil (150)Sample 66 EBLN-90^(*2) (150) 3.35 6.7 11.0 140.3 2.1 3.35 Sample 67EAA-90^(*3) (150) 3.35 6.7 3.35 8.25 140.0 3.35 Sample 68 EEPA-90^(*4)(150) 3.35 6.7 3.35 0 0 142.7 Sample 69 Beef tallow 3.30 6.6 3.3 0 0 3.3hardened oil (200) Sample 70 EBLN-90^(*2) (200) 3.30 6.6 13.5 187 2.83.3 Sample 71 EAA-90^(*3) (200) 3.30 6.6 3.3 11.0 186.6 3.3 Sample 72EEPA-90^(*4) (200) 3.30 6.6 3.3 0 0 189.1

PREPARATION EXAMPLE 5

[0047] Four kinds of beef tallow fatty acid, Extra Bishomo-γ-Linolenic90, Extra Arachidonic 90 and Extra EPA 90 each having compositions shownin Table 8 were used to prepare four kinds of fatty acid calcium saltsaccording to the method used in Preparation Example 3. These fatty acidcalcium salts were used to prepare feeds in compositions shown in Table10. The feeds thus obtained were designated as Samples 73 to 84. Thefeed shown in Table 2 in Preparation Example 1 was used for the basefeed. TABLE 10 Sample Base Linoleic Linolenic BHGLN^(*1) Arachidonic EPANo. Fatty acid (g) feed (kg) acid (g) acid (g) (g) acid (g) (g) Sample73 Beef tallow 3.45 6.9 3.45 0 0 3.45 hardened oil (50) Sample 74EBLN-90^(*2) (50) 3.45 6.9 5.75 42.1 0.63 3.45 Sample 75 EAA-90^(*3)(50) 3.45 6.9 3.45 2.48 42.0 3.45 Sample 76 EEPA-90^(*4) (50) 3.45 6.93.45 0 0 45.26 Sample 77 Beef tallow 3.35 6.7 3.35 0 0 3.35 hardened oil(150) Sample 78 EBLN-90^(*2) (150) 3.35 6.7 10.33 126.2 1.89 3.35 Sample79 EAA-90^(*3) (150) 3.35 6.7 3.35 7.43 126.0 3.35 Sample 80EEPA-90^(*4) (150) 3.35 6.7 3.35 0 0 128.8 Sample 81 Beef tallow 3.256.5 3.25 0 0 3.25 hardened oil (250) Sample 82 EBLN-90^(*2) (250) 3.256.5 13.45 168.3 2.52 3.25 Sample 83 EAA-90^(*3) (250) 3.25 6.5 3.25 9.9167.9 3.25 Sample 84 EEPA-90^(*4) (250) 3.25 6.5 3.25 0 0 170.5

PRODUCTION EXAMPLES 1 to 4

[0048] Four kinds of soybean oil fatty acid, Extra EPA 90, Extraα-Linolenic 70 and safflower oil fatty acid each having compositionsshown in Table 11 were used to produce fatty acid metal salts by meansof an extruder. TABLE 11 Fatty acid composition (% by weight) Soybeanoil Safflower oil Kind of fatty acid fatty acid Extra EPA 90 Extraα-Linolenic 70 fatty acid Myristic acid — — — — Palmitic acid 10.4 — —6.8 Palmitoleic acid — — — — Stearic acid 4.0 — — 2.5 Oleic acid 23.5 —4.0 12.6 Linoleic acid 53.5 — 22.5 77.4 Linolenic acid 8.3 — 73.5 0.1Eicosapentaenoic acid — 92.9 — — Docosahexaenoic acid — 5.9 — — Others —1.2 — —

PRODUCTION EXAMPLE 1

[0049] Soybean oil fatty acid (melting point: −2° C.) and calciumhydroxide which were heated in advance at 40° C. were fed at a rate of100 kg/hr and 20 kg/hr respectively from a raw material-feeding port inthe first barrel of an EA-100 type extruder (manufactured by Suehiro EPMCo., Ltd.). Water was fed at a rate of 3 kg/hr from a charging portpresent at an upper part of the first barrel. Set respectively were atemperature of jackets in the first and second barrels (rawmaterial-feeding parts) at 70° C., a temperature of jackets in the thirdand fourth barrels (kneading and reacting part) at 180° C. and atemperature of jackets in the fifth and sixth barrels (cooling part) at−10° C. to carry out continuous reaction at a screw revolution of 120rounds/minute for 5 hours. After finishing the reaction, a fatty acidcalcium salt product was obtained at a reactivity, an amount and a yieldeach shown in Table 12.

PRODUCTION EXAMPLE 2

[0050] The reaction was carried out in the same manner as in ProductionExample 1, except that substituted were Extra EPA90 (melting point: −44°C., manufactured by NOF Corporation) for soybean oil fatty acid andmagnesium hydroxide of 16 kg/hr for calcium hydroxide of 20 kg/hr andthat a screw revolution of 120 rounds/minute was changed to 100rounds/minute. After finishing the reaction, a fatty acid magnesium saltproduct was obtained at a reactivity, an amount and a yield each shownin Table 12.

PRODUCTION EXAMPLE 3

[0051] The reaction was carried out in the same manner as in ProductionExample 1, except that substituted were Extra α-Linolenic 70 (meltingpoint: −25° C., manufactured by NOF Corporation) for soybean oil fattyacid and magnesium hydroxide of 13 kg/hr for calcium hydroxide of 20kg/hr and that a temperature of the jackets in the third and fourthbarrels (kneading and reacting part) was changed from 180° C. to 100° C.and a temperature of the jackets in the fifth and sixth barrels (coolingpart) was changed from −10° C. to −5° C. After finishing the reaction, afatty acid magnesium salt product was obtained at a reactivity, anamount and a yield each shown in Table 12.

PRODUCTION EXAMPLE 4

[0052] The reaction was carried out in the same manner as in ProductionExample 1, except that safflower oil fatty acid (melting point: −15° C.)was substituted for soybean oil fatty acid and that a temperature of thejackets in the third and fourth barrels (kneading and reacting part) waschanged from 180° C. to 160° C. After finishing the reaction, a fattyacid calcium salt product was obtained at a reactivity, an amount and ayield each shown in Table 12. TABLE 12 Production Example 1 3 4 Kind offatty Soybean oil 2 Extra α- Safflower oil acid fatty acid Extra EPA90Linolenic 70 fatty acid Kind of metal Calcium Magnesium MagnesiumCalcium Amount (kg) 557 566 570 557 Yield (%) 98.0 97.0 98.0 98.0Reactivity (%) 99.9 99.8 99.7 99.5

PRODUCTION EXAMPLE 6

[0053] Four kinds of the fatty acid metal salts obtained in ProductionExamples 1 to 4 were mixed with the base feed by the use of a ribbonmixer in compositions shown in Table 13 to prepare mixed feeds. The feedshown in Table 2 in Preparation Example 1 was used for the base feed.The feeds thus obtained were designated as Samples 85 to 92. Shown inTable 13 were the contents of linoleic acid, linolenic acid andeicosapentaenoic acid (EPA) contained in the mixed feeds. TABLE 13Sample Fatty acid metal Base Linoleic Linolenic EPA No. salt (g) feed(kg) acid (g) acid (g) Sample 85 Soybean oil fatty acid calcium salt3.45 30.98 7.19 3.45 (50) Sample 86 Extra EPA90 fatty acid 3.45 6.903.45 47.11 magnesium salt (50) Sample 87 Extra α-Linolenic 70 fatty acid3.45 17.48 38.00 3.45 magnesium salt (50) Sample 88 Safflower oil fattyacid calcium 3.45 41.73 3.50 3.45 salt (50) Sample 89 Soybean oil fattyacid calcium salt 3.35 78.93 14.56 3.35 (150) Sample 90 Extra EPA90fatty acid 3.35 6.70 3.35 134.3 magnesium salt (150) Sample 91 Extraα-Linolenic 70 fatty acid 3.35 38.43 107.0 3.35 magnesium salt (150)Sample 92 Safflower oil fatty acid calcium 3.35 111.2 3.49 3.35 salt(150)

EXAMPLE 1

[0054] Divided into 18 groups by every 20 head were 360 head of LandRace Yorkshire genus female pigs having an average body weight of 170kg. In a duration extending from 30 days before artificial inseminationup to 3 weeks after the artificial insemination, each of Samples 1 to 18was fed to each group in an amount of 3.5 kg per head a day. Sperms ofDirac genus were fertilized by artificial insemination, and then 3.5 kgper head a day on the average of Sample 1 was fed during a pregnantduration. In the subsequent delivery, determined were a litter size,average days of returning estrus and an average number of delactation ofeach group (20 head). The results thereof are shown in table 14. TABLE14 Average days of Average number Litter size returning estrus ofdelactation (head) (day) (head) Sample 1 11.5 12.2 9.5 Sample 2 13.5 6.811.9 Sample 3 14.8 5.7 13.0 Sample 4 14.7 5.5 12.9 Sample 5 14.7 5.613.0 Sample 6 14.5 5.5 13.0 Sample 7 12.0 11.8 10.2 Sample 8 14.3 6.312.6 Sample 9 14.9 5.8 13.1 Sample 10 15.0 5.8 13.2 Sample 11 15.3 5.913.2 Sample 12 15.2 5.5 13.1 Sample 13 12.0 11.7 10.2 Sample 14 14.6 6.012.8 Sample 15 15.5 5.5 13.6 Sample 16 15.7 5.5 13.9 Sample 17 15.5 5.613.6 Sample 18 15.4 5.5 13.7

[0055] Among Samples 1 to 18 used in the present example, only Samples1, 7 and 13 each had linoleic acid, linolenic acid and eicosapentaenoicacid (EPA) contents of less than 20 g. The respective groups fed withthe feeds compounded with any of soybean oil, sunflower oil, saffloweroil, linseed oil and borage oil showed good breeding results in all ofthe three items as compared with those of the groups fed with Samples 1,7 and 13 compounded with beef tallow hardened oil. That is, the feedscompounded with triglycerides containing linoleic acid and linolenicacid were improved in breeding results.

EXAMPLE 2

[0056] The feeding test was carried out in the same manner as in Example1, except that the number of the female pigs was changed from 360 headto 420 head and 18 groups were changed to 21 groups. The 21 groups eachwere fed with each of Samples 19 to 39. The results thereof are shown intable 15. TABLE 15 Average days of Average number Litter size returningestrus of delactation (head) (day) (head) Sample 19 11.6 12.3 9.7 Sample20 13.8 6.6 12.0 Sample 21 14.3 6.0 12.4 Sample 22 14.5 6.1 12.6 Sample23 14.5 6.1 12.7 Sample 24 14.6 6.1 12.8 Sample 25 14.6 6.2 12.7 Sample26 11.9 12.1 9.9 Sample 27 14.8 6.0 12.8 Sample 28 15.2 5.7 13.4 Sample29 15.4 5.7 13.6 Sample 30 15.6 5.6 13.6 Sample 31 15.6 5.6 13.8 Sample32 15.5 5.6 13.7 Sample 33 12.0 12.0 10.1 Sample 34 15.0 5.9 13.0 Sample35 16.4 5.4 14.5 Sample 36 16.5 5.4 14.7 Sample 37 16.3 5.4 14.5 Sample38 16.5 5.5 14.8 Sample 39 16.3 5.7 14.5

[0057] Among Samples 19 to 39 used in the present example, all ofSamples 19, 26 and 33 each had linoleic acid, linolenic acid andeicosapentaenoic acid (EPA) contents of 20 g or less. The respectivegroups fed with the samples compounded with soybean oil fatty acid,sunflower oil fatty acid, safflower oil fatty acid, Extra α-Linolenic70, linseed oil fatty acid and borage oil fatty acid showed goodbreeding results in all of the three items as compared with those of thegroups fed with Samples 19, 26 and 33 compounded with beef tallowhardened oil fatty acid. That is, the samples compounded with linoleicacid and linolenic acid were improved in breeding results.

EXAMPLE 3

[0058] The feeding test was carried out in the same manner as in Example2, except that each of the 21 groups was fed with Samples 40 to 60 inplace of Samples 19 to 39. The results thereof are shown in table 16.TABLE 16 Average days of Average number Litter size returning estrus ofdelactation (head) (day) (head) Sample 40 11.8 12.5 9.9 Sample 41 14.06.5 12.1 Sample 42 14.8 6.0 13.0 Sample 43 14.9 6.0 13.2 Sample 44 14.86.1 13.0 Sample 45 14.9 6.1 13.3 Sample 46 14.8 6.0 13.1 Sample 47 12.112.3 10.1 Sample 48 14.3 6.1 12.3 Sample 49 15.2 5.8 13.4 Sample 50 15.55.6 13.7 Sample 51 15.5 5.5 13.8 Sample 52 15.4 5.5 13.8 Sample 53 15.55.6 13.8 Sample 54 12.3 12.2 10.2 Sample 55 14.8 6.0 12.9 Sample 56 16.05.8 14.3 Sample 57 16.1 5.5 14.4 Sample 58 16.1 5.4 14.4 Sample 59 16.35.5 14.5 Sample 60 16.3 5.4 14.7

[0059] Among Samples 40 to 60 used in the present example, Samples 40,47 and 54 each had linoleic acid, linolenic acid and EPA contents of 20g or less. The respective groups fed with the samples compounded withfatty acid calcium salts comprising soybean oil fatty acid, sunfloweroil fatty acid, safflower oil fatty acid, Extra α-Linolenic 70, linseedoil fatty acid or borage oil fatty acid showed good breeding results inall of the three items as compared with those of the groups fed withSamples 40, 47 and 54 compounded with calcium salt of fatty acidcontained in beef tallow hardened oil. That is, the samples compoundedwith fatty acid calcium salts containing linoleic acid and linolenicacid were improved in breeding results.

EXAMPLE 4

[0060] The feeding test was carried out in the same manner as in Example1, except that the number of the female pigs was changed from 360 headto 240 head and 18 groups were changed to 12 groups. The 12 groups eachwere fed with each of Samples 61 to 72. The results thereof are shown intable 17. TABLE 17 Average days of Average number Litter size returningestrus of delactation (head) (day) (head) Sample 61 11.5 12.2 9.5 Sample62 14.6 6.3 13.1 Sample 63 14.8 6.0 13.3 Sample 64 14.8 6.0 13.2 Sample65 12.0 12.2 10.5 Sample 66 15.4 5.7 13.9 Sample 67 15.3 5.7 13.9 Sample68 15.6 5.5 13.8 Sample 69 12.6 12.4 10.5 Sample 70 16.0 5.4 14.4 Sample71 16.1 5.7 14.4 Sample 72 16.2 5.6 14.6

[0061] Among Samples 61 to 72 used in the present example, Samples 61,65 and 69 each had linoleic acid, linolenic acid, bishomo-γ-linolenicacid, arachidonic acid and EPA contents of 20 g or less. The respectivegroups fed with the samples compounded with Extra Bishomo-γ-Linolenic90, Extra Arachidonic 90 and Extra EPA 90 showed good breeding resultsin all of the three items as compared with those of the groups fed withSamples 61, 65 and 69 compounded with beef tallow hardened oil fattyacid. That is, the samples compounded with fatty acids containingbishomo-γ-linolenic acid, arachidonic acid and EPA were improved inbreeding results.

EXAMPLE 5

[0062] The feeding test was carried out in the same manner as in Example1, except that the number of the female pigs was changed from 360 headto 400 head and 18 groups were changed to 20 groups and that the 20groups each were fed with each of Samples 73 to 92. The results thereofare shown in table 18. TABLE 18 Average days of Average number Littersize returning estrus of delactation (head) (day) (head) Sample 73 11.312.5 9.5 Sample 74 14.8 6.8 13.3 Sample 75 14.7 6.3 13.3 Sample 76 14.66.1 13.5 Sample 77 12.0 12.3 10.5 Sample 78 15.5 5.7 13.8 Sample 79 15.15.9 13.9 Sample 80 15.6 5.7 13.9 Sample 81 12.6 12.2 10.5 Sample 82 16.15.5 14.5 Sample 83 16.2 5.7 14.6 Sample 84 16.3 5.5 14.6 Sample 85 14.26.4 12.3 Sample 86 14.3 6.3 13.2 Sample 87 14.6 6.1 13.1 Sample 88 14.86.0 13.2 Sample 89 14.5 6.0 12.5 Sample 90 15.4 5.8 13.6 Sample 91 15.35.6 13.7 Sample 92 15.6 5.5 13.8

[0063] Among Samples 73 to 92 used in the present example, Samples 73,77 and 81 each had linoleic acid, linolenic acid, bishomo-γ-linolenicacid, arachidonic acid and EPA contents of 20 g or less. The respectivegroups fed with the samples compounded with Extra Bishomo-γ-Linolenic 90fatty acid calcium salt, Extra Arachidonic 90 fatty acid calcium salt,soybean oil fatty acid calcium salt, Extra EPA 90 fatty acid calciumsalt and fatty acid magnesium salt, Extra α-Linolenic 70 fatty acidcalcium salt and safflower oil fatty acid calcium salt showed goodbreeding results in all of the three items as compared with those of thegroups fed with Samples 73, 77 and 81 compounded with beef tallowhardened oil fatty acid calcium salt.

[0064] Industrial Applicability

[0065] According to the present invention, fed are a fatty acid having12 to 24 carbon atoms which has a melting point falling in a range of−60 to 40° C. and an iodine value falling in a range of 30 to 470 andwhich has 2 to 6 double bonds in a molecule, triglyceride containing theabove fatty acid and a metal salt of the above fatty acid which assumean important part in breeding, whereby breeding results can be elevatedby shortening the days of returning estrus and increasing a litter sizeand the number of delactation. Accordingly, a productivity of young pigsis improved to a large extent, which brings about industrial advantages.

What is claimed is:
 1. A feed adapted to be fed to a female pig forpropagation characterized by comprising at least one lipid selected froma fatty acid having 12 to 24 carbon atoms which has a melting pointfalling in a range of −60 to 40° C. and an iodine value falling in arange of 30 to 470 and which has 2 to 6 double bonds in a molecule, atriglyceride containing said fatty acid and at least one selected from agroup consisting of a calcium salt and a magnesium salt of said fattyacid in a proportion of 0.5 to 10% by weight in terms of said fattyacid.
 2. The feed as described in claim 1, further comprising a basefeed to feed the female pig, blended with said at least one lipid. 3.The feed described in claim 1, wherein the fatty acid is at least oneselected from linoleic acid, linolenic acid, bishomo-γ-linolenic acid,arachidonic acid and eicosapentaenoic acid.
 4. The feed as described incliam 1, wherein said at least one selected from a group consisting of acalcium salt and a magnesium salt of said fatty acid is produced byreacting a fatty acid with a metal oxide or a metal hydroxide by meansof an extruder having at least a raw material-feeding zone, a kneadingand reacting zone and a cooling zone.
 5. The feed as described in claim4, wherein said at least one selected from a group consisting of acalcium salt and a magnesium salt of said fatty acid is produced bycontrolling a temperature of of the raw material-feeding zone in theextruder to 20 to 80° C., a temperature of the kneading and reactingzone to 80 to 200° C. and a temperature of the cooling zone to −20 to 5°C.
 6. The feed as described in claim 1, produced by blending a base feedwith. said at least one selected from a group consisting of a calciumsalt and a magnesium salt of said fatty acid obtained by decomposing orrefining soybean oil, corn oil, rapeseed oil, sunflower oil, saffloweroil, sesame oil, rice oil, beefsteak plant oil, evening primrose oil,borage oil, linseed oil, palm oil or fish oil.
 7. The feed as describedin claim 6, wherein said at least one selected from a group consistingof a calcium salt and a magnesium salt of said fatty acid is a fattyacid calcium salt or a fatty acid magnesium salt containing at least oneselected from linoleic acid, linolenic acid, bishomo-γ-linolenic acid,arachidonic acid and eicosapentaenoic acid in a proportion of 20 to 99%by weight or both of them.